Articles including multi-component fibers and particles and methods of making and using the same

ABSTRACT

An article including multi-component fibers and particles is disclosed. The multi-component fibers include at least a first polymeric composition and a second polymeric composition, are adhered together, and are non-fusing at a temperature of at least 110° C. At least a portion of the external surfaces of the multi-component fibers includes the first polymeric composition. Particles are adhered or directly attached to the first polymeric composition on the external surfaces of at least some of the multi-component fibers along their lengths. The particles include at least one of activated carbon, superabsorbent polymer particles, and abrasive particles. In some embodiments, the particles are distributed throughout the thickness of a web of the multi-component fibers. A method of making the articles is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No. 61/505,165, filed Jul. 7, 2011, the disclosure of which is incorporated by reference in its entirety herein.

BACKGROUND

Various multi-component fibers are known. Examples include fibers that have a low temperature melting or softening sheath covering a higher melting core. Multi-component structures may be useful, for example, for fiber bonding, wherein the sheath, for example, when melted or softened serves as a bonding agent for the core.

Some articles including fibers and particles are known. In some cases, such articles are made from multi-component fibers where one component melts and coalesces. In these cases, the particles are located at the junction points where fibers contact one another. See, for example, International Patent Application Publication No. WO 2010/045053 (Coant et al.).

Some abrasive articles including multi-component fibers and abrasive particles have been described. See, for example, U.S. Pat. No. 5,082,720 (Hayes); U.S. Pat. No. 5,972,463 (Martin et al.); and U.S. Pat. No. 6,017,831 (Beardsley et al.). Typically, make coats and/or size coats are used to hold particles on a surface of a web of the fibers.

SUMMARY

The present disclosure provides, for example, articles including multi-component fibers and particles. The multi-component fibers are non-fusing at a temperature of at least 110° C., which means the fibers maintain their multi-component architecture at least up to that temperature. The particles adhere to a first polymeric composition in the multi-component fibers along the length of the fibers. Therefore, the particles are not located only in the junction points between fibers but may be uniformly distributed. In the method of making the articles disclosed herein, a mixture of fibers and particles is heated to a temperature where the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² when measured at one hertz. At such a temperature, the first polymeric composition becomes tacky and adheres the particles on the lengths of the multi-component fibers.

In one aspect, the present disclosure provides an article including multi-component fibers and particles. The multi-component fibers have external surfaces and include at least a first polymeric composition and a second polymeric composition, with at least a portion of the external surfaces of the multi-component fibers comprising the first polymeric composition. The multi-component fibers are adhered together and are non-fusing at a temperature of at least 110° C. The particles are adhered at least to the first polymeric composition on the external surfaces of at least some of the multi-component fibers along their lengths. The particles comprise at least one of activated carbon and superabsorbent polymer particles.

In another aspect, the present disclosure provides an article including a web of multi-component fibers and particles distributed throughout the thickness of the web. The multi-component fibers have external surfaces and include at least a first polymeric composition and a second polymeric composition, with at least a portion of the external surfaces of the multi-component fibers comprising the first polymeric composition. The multi-component fibers are adhered together and are non-fusing at a temperature of at least 110° C. The particles are directly attached to the first polymeric composition on the external surfaces of at least some of the multi-component fibers along their lengths. The particles comprise at least one of activated carbon, superabsorbent polymer particles, and abrasive particles.

In another aspect, the present disclosure provides a method of making an article. The method includes providing a mixture of particles and multi-component fibers. The multi-component fibers include at least a first polymeric composition and a second polymeric composition, and the particles include at least one of activated carbon, superabsorbent polymer particles, and abrasive particles. The method further includes heating the mixture to a temperature at which the multi-component fibers are non-fusing and at which the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² when measured at one hertz. When heated to such a temperature, at least a portion of the mixture becomes adhered together to form a web, and the particles are dispersed throughout the thickness of the web.

In some embodiments of the foregoing aspects, the particles include activated carbon. In these embodiments, the articles described herein are useful, for example, for filtration. Carbon filters as articles according to and/or made according to the present disclosure are typically easy and inexpensive to assemble without the use of sophisticated equipment. Such filters are typically flexible, which may be advantageous for some configurations, with the activated carbon particles being strongly adhered to the multi-component fibers.

In other embodiments of the foregoing aspects, the particles include abrasive particles, and the articles described herein are useful as abrasive articles. In these embodiments, the articles are surprisingly effective as abrasives even in the absence of make coats and size coats. Abrasive articles according to the present disclosure are typically prepared without much loss of the abrasive particles.

In this application, terms such as “a”, “an” and “the” are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terms “a”, “an”, and “the” are used interchangeably with the term “at least one”. The phrases “at least one of” and “comprises at least one of” followed by a list refers to any one of the items in the list and any combination of two or more items in the list. All numerical ranges are inclusive of their endpoints and non-integral values between the endpoints unless otherwise stated.

The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. It is to be understood, therefore, that the drawings and following description are for illustration purposes only and should not be read in a manner that would unduly limit the scope of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of the present disclosure, reference is now made to the detailed description along with the accompanying figures and in which:

FIG. 1 is a partial schematic view of an exemplary article according to the present disclosure;

FIGS. 2A-2D are schematic cross-sections of four exemplary fibers described herein;

FIGS. 3A-3E are schematic perspective views of various fibers described herein;

FIGS. 4A and 4B are photomicrographs of exemplary articles according to the present disclosure, in which activated carbon is adhered to the surfaces of multi-component fibers; and

FIG. 5 is a photograph of the patterned abrasive article of Example 2.

DETAILED DESCRIPTION

FIG. 1 illustrates a portion of an exemplary article according to and/or made according to the present disclosure. The article includes multi-component fibers 4 and particles 2. The multi-component fibers are adhered together (e.g., autogenously bonded) at junction points 6, and the particles 2 are adhered on the external surfaces of at least some of the multi-component fibers 4. As illustrated in FIG. 1, the particles 2 are located along the lengths of the multi-component fibers 4, which means that the particles are not located only at the junction points 6 of the fibers.

In some embodiments, particles located “along the lengths” of the multi-component fibers means that the particles are located substantially along the entire length of the multi-component fibers. The particles may be randomly distributed along the entire length of the multi-component fibers. In these embodiments, the particles need not cover the entire external surface of the multi-component fibers to be considered to be located along the entire length of the multi-component fibers. The particles may be uniformly distributed, or not, depending, for example, on the level of mixing of the multi-component fibers and the particles, as described below, and the particle size distribution.

In some embodiments, including the embodiment illustrated in FIG. 1, the particles 2 are directly attached to the external surfaces of at least some of the multi-component fibers 4. “Directly attached” means that there is no adhesive or other binder between the particles and the first polymeric composition on the external surface of the fibers. The first polymeric composition in the multi-component fibers typically functions as the adhesive that holds the fibers together and adheres the particles to the fibers.

Fibers useful for the articles disclosed herein include a variety of cross-sectional shapes. Useful fibers include those having at least one cross-sectional shape selected from the group consisting of circular, prismatic, cylindrical, lobed, rectangular, polygonal, or dog-boned. The fibers may be hollow or not hollow, and they may be straight or have an undulating shape. Differences in cross-sectional shape allow for control of active surface area, mechanical properties, and interaction with particles or other components. In some embodiments, the fiber according to the present disclosure has a circular cross-section or a rectangular cross-section. Fibers having a generally rectangular cross-section shape are also typically known as ribbons. Fibers are useful, for example, because they provide large surface areas relative the volume they displace.

Exemplary embodiments of multi-component fibers useful for practicing the present disclosure include those with cross-sections illustrated in FIGS. 2A-2D. A core-sheath configuration, as shown in FIG. 2B or 2C, may be useful, for example, because of the large surface area of the sheath. In these configurations, the external surface of the fiber is typically made from a single composition. It is within the scope of the present disclosure for the core-sheath configurations to have multiple sheaths. Other configurations, for example, as shown in FIGS. 2A and 2D provide options that can be selected depending on the intended application. In the segmented pie wedge (see, e.g., FIG. 2A) and the layered (see, e.g., FIG. 2D) configurations, typically the external surface is made from more than one composition.

Referring to FIG. 2A, a pie-wedge fiber 10 has a circular cross-section 12, a first polymeric composition located in regions 16 a and 16 b, and a second polymeric composition located in regions 14 a and 14 b. Other regions in the fiber (18 a and 18 b) may include a third component (e.g., a third, different polymeric composition) or may independently include the first polymeric composition or the second polymeric composition.

In FIG. 2B, fiber 20 has circular cross-section 22, sheath 24 of a first polymeric composition, and core 26 of a second polymeric composition. FIG. 2C shows fiber 30 having a circular cross-section 32 and a core-sheath structure with sheath 34 of a first polymeric composition and plurality of cores 36 of a second polymeric composition.

FIG. 2D shows fiber 40 having circular cross-section 42, with five layered regions 44 a, 44 b, 44 c, 44 d, 44 e, which comprise alternatively at least the first polymeric composition and the second polymeric composition. Optionally, a third, different polymeric composition may be included in at least one of the layers.

FIGS. 3A-3E illustrate perspective views of various embodiments of multi-component fibers useful in the articles according to the present disclosure. FIG. 3A illustrates a fiber 50 having a triangular cross-section 52. In the illustrated embodiment, the first polymeric composition 54 exists in one region, and the second polymeric composition 56 is positioned adjacent the first polymeric composition 54.

FIG. 3B illustrates a ribbon-shaped embodiment 70 having a generally rectangular cross-section and an undulating shape 72. In the illustrated embodiment, a first layer 74 comprises the first polymeric composition, while a second layer 76 comprises the second polymeric composition.

FIG. 3C illustrates a coiled or crimped multi-component fiber 80 useful for articles according to the present disclosure. The distance between coils, 86, may be adjusted according to the properties desired.

FIG. 3D illustrates a fiber 100 having a cylindrical shape, and having a first annular component 102, a second annular component 104, the latter component defining hollow core 106. The first and second annular components typically comprise the first polymeric composition and the second polymeric composition, respectively. The hollow core 106 may optionally be partially or fully filled with an additive (e.g., a curing agent or tackifier) for one of the annular components 102, 104.

FIG. 3E illustrates a fiber with a lobed-structure 110, the example shown having five lobes 112 with outer portions 114 and an interior portion 116. The outer portions 114 and interior portion 116 typically comprise the first polymeric composition and the second polymeric composition, respectively.

The aspect ratio of multi-component fibers described herein may be, for example, at least 3:1, 4:1, 5:1, 10:1, 25:1, 50:1, 75:1, 100:1, 150:1, 200:1, 250:1, 500:1, 1000:1, or more; or in a range from 2:1 to 1000:1. Larger aspect ratios (e.g., having aspect ratios of 10:1 or more) may more easily allow the formation of a network of multi-component fibers and may allow for more particles to be adhered to the external surfaces of the fibers.

Multi-component fibers useful for the articles according to the present disclosure include those having a length up to 60 mm, in some embodiments, in a range from 2 mm to 60 mm, 3 mm to 40 mm, 2 mm to 30 mm, or 3 mm to 20 mm. Typically, the multi-component fibers disclosed herein have a maximum cross-sectional dimension up to 300 (in some embodiments, up to 250, 200, 150, 100, 90, 80, 70, 60, 50, 40, or 30) micrometers. For example, the fiber may have a circular cross-section with an average diameter in a range from 1 micrometer to 300 micrometers, 1 micrometer to 100 micrometers, 10 micrometers to 50 micrometers, 10 micrometers to 30 micrometers, or 17 micrometers to 23 micrometers. In another example, the fiber may have a rectangular cross-section with an average length (i.e., longer cross-sectional dimension) in a range from 1 micrometer to 300 micrometers, 1 micrometer to 100 micrometers, 10 micrometers to 50 micrometers, 10 micrometers to 30 micrometers, or 17 micrometers to 23 micrometers.

In some embodiments, multi-component fibers useful for the articles and methods according to the present disclosure are non-fusing at a temperature of at least 110° C. (in some embodiments, at least 120° C., 125° C., 150° C., or at least 160° C.). When multi-component fibers are non-fusing at any of these temperatures, it will be understood that they are also non-fusing below that temperature. In some embodiments, multi-component fibers useful for the articles and methods according to the present disclosure are non-fusing at a maximum temperature of up to 200° C. “Non-fusing” fibers can autogenously bond (i.e., bond without the addition of pressure between fibers) without significant loss of architecture, for example, a core-sheath configuration. The spatial relationship between the first polymeric composition, the second polymeric composition, and optionally any other component of the fiber is generally retained in non-fusing fibers. Typically multi-component fibers (e.g., fibers with a core-sheath configuration) undergo so much flow of the sheath composition during autogenous bonding that the core-sheath structure is lost as the sheath composition becomes concentrated at fiber junctions and the core composition is exposed elsewhere. That is, typically multi-component fibers are fusing fibers. This loss of structure typically results in the loss of the functionality of the fiber provided by the sheath component. In non-fusing fibers (e.g., core-sheath fibers) heat causes little or no flow of the sheath composition so that the sheath functionality is retained along the majority of the multi-component fibers.

To evaluate whether fibers are non-fusing at a particular temperature, the following test method is used. The fibers are cut to 6 mm lengths, separated, and formed into a flat tuft of interlocking fibers. The larger cross-sectional dimension (e.g., the diameter for a circular cross-section) of twenty of the cut and separated fibers is measured and the median recorded. The tufts of the fibers are heated in a conventional vented convection oven for 5 minutes at the selected test temperature. Twenty individual separate fibers are then selected and their larger cross-section dimension (e.g., diameter) measured and the median recorded. The fibers are designated as “non-fusing” if there is less than 20% change in the measured dimension after the heating.

Typically, the dimensions of the multi-component fibers used together in an article and/or method according to the present disclosure, and components making up the fibers are generally about the same, although use of fibers with even significant differences in compositions and/or dimensions may also be useful. In some applications, it may be desirable to use two or more different groups of multi-component fibers (e.g., at least one different polymer or resin, one or more additional polymers, different average lengths, or otherwise distinguishable constructions), where one group offers a certain advantage(s) in one aspect, and other group a certain advantage(s) in another aspect.

Fibers described herein can generally be made using techniques known in the art for making multi-component (e.g., bi-component) fibers. Such techniques include fiber spinning (see, e.g., U.S. Pat. No. 4,406,850 (Hills), U.S. Pat. No. 5,458,972 (Hagen), U.S. Pat. No. 5,411,693 (Wust), U.S. Pat. No. 5,618,479 (Lijten), and U.S. Pat. No. 5,989,004 (Cook)).

Each component of the fibers, including the first polymeric composition, second polymeric composition, and any additional polymers, can be selected to provide desirable performance characteristics.

In some embodiments, the first polymeric composition in the multi-component fibers has a softening temperature up to 150° C. (in some embodiments, up to 140° C., 130° C., 120° C., 110° C., 100° C., 90° C., 80° C., or 70° C. or in a range from 80° C. to 150° C.). The softening temperature of the first polymeric composition is determined using a stress-controlled rheometer (Model AR2000 manufactured by TA Instruments, New Castle, Del.) according to the following procedure. A sample of the first polymeric composition is placed between two 20 mm parallel plates of the rheometer and pressed to a gap of 2 mm ensuring complete coverage of the plates. A sinusoidal frequency of 1 Hz at 1% strain is then applied over a temperature range of 80° C. to 200° C. The resistance force of the molten resin to the sinusoidal strain is proportional to its modulus which is recorded by a transducer and displayed in graphical format. Using rheometeric software, the modulus is mathematically split into two parts: one part that is in phase with the applied strain (elastic modulus—solid-like behavior), and another part that is out of phase with the applied strain (viscous modulus—liquid-like behavior). The temperature at which the two moduli are identical (cross-over temperature) is the softening temperature, as it represents the temperature above which the resin began to behave predominantly like a liquid.

For any of the embodiments of multi-component fibers disclosed herein, the first polymeric composition may be a single polymeric material, a blend of polymeric materials, or a blend of at least one polymer and at least one other additive. The softening temperature of the first polymeric composition, advantageously, may be above the storage temperature of the multi-component fiber. The desired softening temperature can be achieved by selecting an appropriate single polymeric material or combining two or more polymeric materials. For example, if a polymeric material softens at too high of a temperature it can be decreased by adding a second polymeric material with a lower softening temperature. Also, a polymeric material may be combined with, for example, a plasticizer to achieve the desired softening temperature.

Exemplary polymers that have or may be modified to have a softening temperature up to 150° C. (in some embodiments, up to than 140° C., 130° C., 120° C., 110° C., 100° C., 90° C., 80° C., or 70° C. or in a range from 80° C. to 150° C.) include at least one of (i.e., includes one or more of the following in any combination) ethylene-vinyl alcohol copolymer (e.g., with softening temperature of 156 to 191° C., available from EVAL America, Houston, Tex., under the trade designation “EVAL G176B”), thermoplastic polyurethane (e.g., available from Huntsman, Houston, Tex., under the trade designation “IROGRAN A80 P4699”), polyoxymethylene (e.g., available from Ticona, Florence, Ky., under the trade designation “CELCON FG40U01”), polypropylene (e.g., available from Total, Paris, France, under the trade designation “5571”), polyolefins (e.g., available from ExxonMobil, Houston, Tex., under the trade designation “EXACT 8230”), ethylene-vinyl acetate copolymer (e.g., available from AT Plastics, Edmonton, Alberta, Canada), polyester (e.g., available from Evonik, Parsippany, N.J., under the trade designation “DYNAPOL” or from EMS-Chemie AG, Reichenauerstrasse, Switzerland, under the trade designation “GRILTEX”), polyamides (e.g., available from Arizona Chemical, Jacksonville, Fla., under the trade designation “UNIREZ 2662” or from E. I. du Pont de Nemours, Wilmington, Del., under the trade designation “ELVAMIDE 8660”), phenoxy (e.g., from Inchem, Rock Hill S.C.), vinyls (e.g., polyvinyl chloride form Omnia Plastica, Arsizio, Italy), or acrylics (e.g., from Arkema, Paris, France, under the trade designation “LOTADEREX 8900”). In some embodiments, the first polymeric composition comprises a partially neutralized ethylene-methacrylic acid copolymer commercially available, for example, from E. I. duPont de Nemours & Company, under the trade designations “SURLYN 8660,” “SURLYN 1702,” “SURLYN 1857,” and “SURLYN 9520”). In some embodiments, the first polymeric composition comprises a mixture of a thermoplastic polyurethane obtained from Huntsman under the trade designation “IROGRAN A80 P4699”, a polyoxymethylene obtained from Ticona under the trade designation “CELCON FG40U01”, and a polyolefin obtained from ExxonMobil Chemical under the trade designation “EXACT 8230”. In some embodiments, multi-component fibers useful for the articles according to the present disclosure may comprise in a range from 5 to 85 (in some embodiments, 5 to 40, 40 to 70, or 60 to 70) percent by weight of the first polymeric composition.

In some embodiments of articles and methods according to the present disclosure, the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² at a frequency of about 1 Hz at a temperature of at least 80° C. In these embodiments, typically the first polymeric composition is tacky at the temperature of 80° C. and above. In some embodiments, the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² at a frequency of about 1 Hz at a temperature of at least 85° C., 90° C., 95° C., or 100° C. For any of these embodiments, the modulus is measured using the method described above for determining softening temperature except the modulus is determined at the selected temperature (e.g., 80° C., 85° C., 90° C., 95° C., or 100° C.).

In some embodiments of multi-component fibers useful for the articles and methods disclosed herein, the second polymeric composition has a melting point of at least 130° C. (in some embodiments, at least 140° C. or 150° C.; in some embodiments, in a range from 130° C. to 220° C., 150° C. to 220° C., or 160° C. to 220° C.). Exemplary useful second polymeric compositions include at least one of (i.e., includes one or more of the following in any combination) an ethylene-vinyl alcohol copolymer (e.g., available from EVAL America, under the trade designation “EVAL G176B”), polyamide (e.g., available from E. I. du Pont de Nemours under the trade designation “ELVAMIDE” or from BASF North America, Florham Park, N.J., under the trade designation “ULTRAMID”), polyoxymethylene (e.g., available from Ticona under the trade designation “CELCON”), polypropylene (e.g., from Total), polyester (e.g., available from Evonik under the trade designation “DYNAPOL” or from EMS-Chemie AG under the trade designation “GRILTEX”), polyurethane (e.g., available from Huntsman under the trade designation “IROGRAN”), polysulfone, polyimide, polyetheretherketone, or polycarbonate. As described above for the first polymeric compositions, blends of polymers and/or other components can be used to make the second polymeric compositions. For example, a thermoplastic having a melting point of less than 130° C. can be modified by adding a higher-melting thermoplastic polymer. In some embodiments, the second polymeric composition is present in a range from 5 to 40 percent by weight, based on the total weight of the multi-component fiber. The melting temperature is measured by differential scanning calorimetry (DSC). In cases where the second polymeric composition includes more than one polymer, there may be two melting points. In these cases, the melting point of at least 130° C. is the lowest melting point in the second polymeric composition.

Optionally, fibers described herein may further comprise other components (e.g., additives and/or coatings) to impart desirable properties such as handling, processability, stability, and dispersability. Exemplary additives and coating materials include antioxidants, colorants (e.g., dyes and pigments), fillers (e.g., carbon black, clays, and silica), and surface applied materials (e.g., waxes, surfactants, polymeric dispersing agents, talcs, erucamide, gums, and flow control agents) to improve handling.

Surfactants can be used to improve the dispersibility or handling of multi-component fibers described herein. Useful surfactants (also known as emulsifiers) include anionic, cationic, amphoteric, and nonionic surfactants. Useful anionic surfactants include alkylarylether sulfates and sulfonates, alkylarylpolyether sulfates and sulfonates (e.g., alkylarylpoly(ethylene oxide) sulfates and sulfonates, preferably those having up to about 4 ethyleneoxy repeat units, including sodium alkylaryl polyether sulfonates such as those known under the trade designation “TRITON X200”, available from Rohm and Haas, Philadelphia, Pa.), alkyl sulfates and sulfonates (e.g., sodium lauryl sulfate, ammonium lauryl sulfate, triethanolamine lauryl sulfate, and sodium hexadecyl sulfate), alkylaryl sulfates and sulfonates (e.g., sodium dodecylbenzene sulfate and sodium dodecylbenzene sulfonate), alkyl ether sulfates and sulfonates (e.g., ammonium lauryl ether sulfate), and alkylpolyether sulfate and sulfonates (e.g., alkyl poly(ethylene oxide) sulfates and sulfonates, preferably those having up to about 4 ethyleneoxy units). Useful nonionic surfactants include ethoxylated oleoyl alcohol and polyoxyethylene octylphenyl ether. Useful cationic surfactants include mixtures of alkyl dimethylbenzyl ammonium chlorides, wherein the alkyl chain has from 10 to 18 carbon atoms. Amphoteric surfactants are also useful and include sulfobetaines, N-alkylaminopropionic acids, and N-alkylbetaines. Surfactants may be added to the fibers disclosed herein, for example, in an amount sufficient on average to make a monolayer coating over the surfaces of the fibers to induce spontaneous wetting. Useful amounts of surfactants may be in a range, for example, from 0.05 to 3 percent by weight, based on the total weight of the multi-component fiber.

Polymeric dispersing agents may also be used, for example, to promote the dispersion of fibers described herein in a chosen medium and at the desired application conditions (e.g., pH and temperature). Exemplary polymeric dispersing agents include salts (e.g., ammonium, sodium, lithium, and potassium) of polyacrylic acids of greater than 5000 average molecular weight, carboxy modified polyacrylamides (available, for example, under the trade designation “CYANAMER A-370” from Cytec Industries, West Paterson, N.J.), copolymers of acrylic acid and dimethylaminoethylmethacrylate, polymeric quaternary amines (e.g., a quaternized polyvinyl-pyrollidone copolymer (available, for example, under the trade designation “GAFQUAT 755” from ISP Corp., Wayne, N.J.) and a quaternized amine substituted cellulosic (available, for example, under the trade designation “JR-400” from Dow Chemical Company, Midland, Mich.), cellulosics, carboxy-modified cellulosics (e.g., sodium carboxy methycellulose (available, for example, under the trade designation ““NATROSOL CMC Type 7L” from Hercules, Wilmington, Del.), and polyvinyl alcohols. Polymeric dispersing agents may be added to the fibers disclosed herein, for example, in an amount sufficient on average to make a monolayer coating over the surfaces of the fibers to induce spontaneous wetting. Useful amounts of polymeric dispersing agents may be in a range, for example, from 0.05 to 5 percent by weight, based on the total weight of the fiber.

Examples of antioxidants that may be useful additives in the multi-component fibers include hindered phenols (available, for example, under the trade designation “IRGANOX” from Ciba Specialty Chemical, Basel, Switzerland). Typically, antioxidants are used in a range from 0.1 to 1.5 percent by weight, based on the total weight of the fiber, to retain useful properties during extrusion and through the life of the article.

In some embodiments of the fibers useful for practicing the present disclosure, the fibers may be crosslinked, for example, through radiation or chemical means. Chemical crosslinking can be carried out, for example, by incorporation of thermal free radical initiators, photoinitiators, or ionic crosslinkers. When exposed to a suitable wavelength of light, for example, a photoinitiator can generate free radicals that cause crosslinking of polymer chains. With radiation crosslinking, initiators and other chemical crosslinking agents may not be necessary. Suitable types of radiation include any radiation that can cause crosslinking of polymer chains such as actinic and particle radiation (e.g., ultraviolet light, X-rays, gamma radiation, ion beam, electronic beam, or other high-energy electromagnetic radiation). Crosslinking may be carried out to a level at which, for example, an increase in modulus of the first polymeric composition is observed.

Depending on the application, particles useful for practicing the present disclosure have sizes, for example, in a range from 100 micrometers to 3000 micrometers (i.e., about 140 mesh to about 5 mesh (ANSI)) (in some embodiments, in a range from 1000 micrometers to 3000 micrometers, 1000 micrometers to 2000 micrometers, 1000 micrometers to 1700 micrometers (i.e., about 18 mesh to about 12 mesh), 850 micrometers to 1700 micrometers (i.e., about 20 mesh to about 12 mesh), 850 micrometers to 1200 micrometers (i.e., about 20 mesh to about 16 mesh), 600 micrometers to 1200 micrometers (i.e., about 30 mesh to about 16 mesh), 425 micrometers to 850 micrometers (i.e., about 40 to about 20 mesh), or 300 micrometers to 600 micrometers (i.e., about 50 mesh to about 30 mesh). In some embodiments, the particles have a particle size in a range from 500 nanometers to 50 micrometers. In some embodiments, the particles have a particle size up to 25 micrometers, which may be in a range from 500 nanometers to 25 micrometers.

The ratio of particles to multi-component fibers useful for articles and methods of the present disclosure depends, for example, on the application, the crossover point density in the fibers, the shape of the particles, and the particle size distribution. In some embodiments, the maximum amount of particles useful in the articles disclosed herein is the closest packing density of the particles. Useful weight ratios for a given particle and a given application are described below. In some embodiments, mixtures and articles comprising only the particles and the multi-component particles are useful, while in other embodiments, other suitable components may be added to the article or mixture depending on the application as described below.

The method of making an article according to the present disclosure includes providing a mixture of particles and multi-component fibers. Mixing can be carried out by techniques involving mechanical and/or electrostatic mixing of particles. Solvents or water can optionally be included to assist in uniformly mixing the particles and the fibers. In some embodiments, however, the mixing of the particles and the multi-component fibers is a solventless process, which is advantageous because no heating is necessary to evaporate residual water or solvents, which can eliminate process steps and reduce cost. Mixing can be carried out, for example, via convective mixing, diffusive mixing, and shear mixing mechanisms. For example, mixing the particles with the multi-component fibers can be carried out using conventional tumbling mixers (e.g., V-blender, double cone, or rotating cube); convective mixers (e.g., ribbon blender, nautamixer); fluidized bed mixers; or high-shear mixers. In some embodiments, the particles and multi-component fibers are tumbled together in a suitable container. In some embodiments, before the multi-component fibers and particles are mixed using such processes (e.g., tumbling), the multi-component fibers are separated to increase the exposed surface area of the fibers. The multi-component fibers may be in bundles when they are formed, and suitable methods such as subjecting the fibers to a grinder may be useful for separating the fibers and exposing their surfaces. In other embodiments, the multi-component fibers may first be formed into a web, for example, by air-laying and thermally bonding, and the resulting web may be shaken together with the particles. In these embodiments, air-laying the fibers can separate any bundles of fibers and increase their exposed surface area.

The method according to the present disclosure includes heating the mixture of the particles and the multi-component fibers to a temperature at which the multi-component fibers are non-fusing and at which the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² when measured at a frequency of one hertz. The temperature is above the softening temperature of the first polymeric composition and includes any of the ranges of softening temperatures for the first polymeric composition described above. At the temperature, the first polymeric composition will become tacky, and the fibers can adhere to each other and to the particles to form a web. The particles are typically distributed throughout the thickness of the web. In some embodiments, the mixture is placed in a mold before it is heated. Pressure may be applied to the mold, if desired, to consolidate the pack of particles and multi-component fibers. The mold can have any shape depending on the desired application.

In some embodiments, the particles are activated carbon particles. As used herein, “activated carbon” refers to highly porous carbon having a random or amorphous structure. Such particles are also known as charcoal particles and activated charcoal particles. Useful activated carbon particles may have an average particle size in a range from 500 nanometers to 10 millimeters (mm) (e.g., from 1 micrometer to 1 mm, 10 micrometers to 500 micrometers, 10 micrometers mm to 50 micrometers, or 500 nanometers to 50 micrometers). Typically the activated carbon particles have pores that are large enough to take in, for example, impurities when used in a filtration application. In some embodiments, the interior pores have a median pore size in a range from 0.3 nanometers (nm) to 10 nm (e.g., 0.3 nm to 3 nm, 2 nm to 7 nm, 4 nm to 7 nm, 8 nm to 10 nm, or 4 nm to 10 nm). The pore sizes may be unimodal, or the activated carbon particles may have a bimodal porous structure wherein the pores have two different median sizes selected from any of the listed ranges.

Activated carbon products useful for practicing the present disclosure include granules and pellets of activated carbon available, for example, from Calgon Carbon, Inc. (Pittsburgh, Pa.), MeadWestvaco Corporation (Charleston, S.C.), EMD Chemicals (Gibbstown, N.J.), and Kuraray Chemical Co., Ltd. (Osaka, Japan). Activated carbon from any source can be used, including that derived from bituminous coal or other forms of coal, or from pitch, coconut shells, corn husks, polyacrylonitrile (PAN) polymers, charred cellulosic fibers or materials, and wood. Activated carbon particles can, for example, be formed directly by activation of coal or other materials, or by grinding carbonaceous material to a fine powder, agglomerating it with pitch or other adhesives, and then converting the agglomerate to activated carbon.

In some embodiments, activated carbon useful for practicing the present disclosure is provided with functional groups to modify its surface properties. For example, during the activation stage, the carbon can be exposed to nitric acid to add carboxylic acid groups, hydrogen chloride to add chlorine groups, to oxygen or water vapor to add oxygen or hydroxyl groups, to ammonia to add amine groups, and to hydrogen to add hydrogen atoms. Methods of surface modification of activated carbon to produce acidic, basic, and neutral functional groups are described in Shen et al., “Surface Chemical Functional Groups Modification of Porous Carbon”, Recent Patents on Chemical Engineering, 2008, 1, 27-40. Alternatively, a compound such as a non-gaseous molecule may be added to the carbon prior to activating it or prior to a post-treatment step, wherein the compound reacts at elevated temperature to add functional groups to the activated carbon. Such a process is described, for example, in U.S. Pat. No. 5,521,008, (Lieberman et al.).

The weight ratio of the multi-component fibers to activated carbon particles may be, for example, in a range from 10:1 to 1:1, in some embodiments, in a range from 8:1 to 1:1, 8:1 to 2:1, or 8:1 to 4:1.

Articles according to and/or made according to the present disclosure in which the particles are activated carbon particles may be useful for filtration applications. Known as an adsorbent, activated carbon can take up and hold on its surface dissolved organic contaminants (e.g., pesticidal residues and organic vapors), and it can also remove chlorine from, for example, drinking water. Other particles may be useful in combination with the activated carbon and the multi-component fibers for filtration applications. For example, metal ion exchange zeolite sorbents, ion exchange resins, antimicrobial agents, activated alumina, and particulate filter media may be useful additives. In some embodiments, the article disclosed herein may be useful in combination with a sand filter or other particulate filter. In some embodiments, the article and mixture according to the present disclosure further comprises sand.

Articles including carbon particles can be useful, for example, for gravity filtration applications, filters for refrigerators that dispense chilled drinking water and ice, and other water filtration applications. Using the methods disclosed herein, an activated carbon filter can be assembled without the use of sophisticated equipment because of the adhesive nature of the fibers at relative low temperatures (e.g., 80° C.). Accordingly, articles according to and/or made according to the present disclosure may be useful for water filtration in rural areas of developing countries.

An article according to the present disclosure can be formed into any desirable shape using a mold, for example. In some embodiments, filtration articles disclosed herein may be formed as cylinders or discs. The cylinders or discs may be provided with grooves or dimples to increase the surface area of the resulting filter. In some embodiments, the article according to the present disclosure may be in the form of a hollow cylinder, which may be tube-shaped such that there is a core and a wall thickness. In some typical water filtration applications, water may be directed to flow radially from the outside diameter (OD) surface of the tube to the inside diameter (ID) and then out one end of the core. Optionally, pressure may be used to consolidate the mixture in the mold before or during heating. Heating may be carried out in a conventional oven or using microwave, infrared, or radio frequency heating. The article may be free-standing when it is released from the mold. In other embodiments, the mixture is introduced into a casing before the heating, wherein the casing is a pipe or cylinder, and wherein at least a portion of the mixture becomes adhered to the casing.

Photomicrographs of exemplary articles according to the present disclosure in which activated carbon 202 is adhered to the surfaces of multi-component fibers 204 are shown in FIGS. 4A and 4B.

In some embodiments, the particles are abrasive particles, and the articles according to the present disclosure are abrasive articles. These articles can be used for abrasive cutting or shaping, polishing, or cleaning of metals, wood, plastics, and other materials. Additionally, abrasive particles on the multi-component fiber surfaces can provide friction (e.g., for anti-slip applications).

Abrasives particles useful for practicing the present disclosure can be granules of regular or nonregular shape, of virtually any size, and selected from a broad variety of classes of natural or synthetic, abrasive, mineral particulate, such as silicon carbide, aluminum oxide (e.g., ceramic aluminum oxide, heat-treated aluminum oxide, and white-fused aluminum oxide), cubic boron nitride, ceramic beads or grains such as abrasive materials available from 3M Company, St. Paul, Minn., under the trade designation “CUBITRON”, alumina zirconia, diamond, ceria (that is, cerium oxide), garnet, flint, silica, pumice, calcium carbonate, plastic abrasive grains (e.g., made of polyester, polyvinylchloride, methacrylates, polycarbonates, melamine, and polystyrene), crushed plant materials (e.g., shells such as walnut shells and pits such as apricot, peach, and avocado pits), and mixtures of one or more of these materials. The ultimate use of the abrasive article will determine what abrasive particles are most suitable. In some embodiments, the abrasive particles comprise at least one of ceria, silicon carbide, and cubic boron nitride particles. In some embodiments, the abrasive particles comprise ceria particles (that is, cerium oxide particles).

Conventional methods of creating an abrasive article typically rely on first coating a suitable substrate, which may be a prebonded fiber web, with a durable binder resin (that is, make coat precursor) and abrasive particles or other materials, and curing the abrasive article. The particles may be applied to the fibers in a slurry with a durable binder resin. Typically, a size coat is applied over the make coat precursor and the particles to achieve durability, toughness, and functionality. Such a process typically requires high performance resin systems that contain solvents and other hazardous chemicals that necessitate additional careful monitoring to ensure adequate cure with minimization of residual ingredients as well as sophisticated pollution control schemes to control harmful solvent emissions.

The multi-component fibers disclosed herein allow simplification to the overall abrasive- or particle-holding binder systems by elimination of solvent-coating techniques and elimination even of the need for additional bonding agents between the particles and the multi-component fibers. Typically, in the abrasive articles disclosed herein, the particles are directly attached to the first polymeric composition on the external surface of the fibers without the use of a make coat or other binder. In some embodiments, articles according to the present disclosure do not include a size coat. In other embodiments, it may be useful to provide a size coat using conventional techniques.

In some embodiments of the method of making at article disclosed herein, wherein the article is an abrasive article, the multi-component fibers are made into a web, for example, by air-laying and thermally bonding at a temperature at which the multi-component fibers are non-fusing and at which the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² when measured at a frequency of one hertz. The resulting web may be shaken together with the abrasive particles and the mixture heated to a temperature at which the multi-component fibers are non-fusing and at which the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² when measured at a frequency of one hertz. At this temperature, the first polymeric composition will be tacky, and the abrasive particles will adhere to the fibers. Using this method, the abrasive particles will be distributed throughout the thickness of the web.

The weight ratio of the abrasive particles to the multi-component fibers may be, for example, in a range from 10:1 to 1:1, in some embodiments, in a range from 8:1 to 1:1 or from 5:1 to 1:5, depending on the identity of the abrasive particle.

The abrasive articles according to and/or made according to some embodiments of the present disclosure have good polishing capabilities. However, the construction of the articles disclosed herein provides advantages over typical commercial processes. For example, in typical commercial processes, ceria is applied as a slurry. Used ceria slurries may either be recovered for reuse or disposed of, both of which can result in higher cost associated with equipment and material loss. In contrast, the multi-component fibers described herein can adhere a large quantity of ceria particles without significant material loss. Also, in use, abrasive articles which have abrasive particles coated only on one surface, which is typical for conventional abrasives, may lose their abrasive capability more quickly than when abrasive particles are located throughout the web of multi-component fibers as in the present applications. Furthermore, even though they have a relatively simple construction, which may include only multi-component fibers and particles (e.g., with no size coat), the articles disclosed herein have remarkably good abrasive performance.

It should be understood that an abrasive article according to the present disclosure must be usable as an abrasive article. Accordingly, it should be understood that the abrasive articles disclosed herein are not located in or bonded to a fracture in a subterranean formation such as a hydrocarbon (e.g., oil or gas) bearing geological formation. Similarly, in the method disclosed herein, heating the mixture to a temperature at which the multi-component fibers are non-fusing and at which the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² at a temperature of at least 80° C. measured at a frequency of one hertz does not include injecting the mixture of microspheres and multi-component fibers into a subterranean formation such as a hydrocarbon (e.g., oil or gas) bearing geological formation or into a fracture in such a formation.

In some embodiments of the articles and methods of the present disclosure, the particles are superabsorbent polymer (SAP) particles. Examples of SAP materials include the alkali metal and ammonium salts of poly(acrylic acid) and poly(methacrylic acid), poly(acrylamides), poly(vinyl ethers), maleic anhydride copolymers with vinyl ethers and alpha-olefins, poly(vinyl pyrolidone), poly(vinyl morpholinone), poly(vinyl alcohol), and mixtures and copolymers thereof. SAP materials are widely commercially available (e.g., from Evonik Industries, Krefeld, Germany, under the trade designation “FAVOR” or from Stockhausen Corporation of Greensboro, N.C., under the trade designation “FAVOR SXM 880”). The SAP particles may be in any of a wide variety of geometric forms including fibers, flakes, rods, spheres, or needles.

In some embodiments, the article of the present disclosure may be an absorbent component in an absorbent article comprising a liquid permeable topsheet, a liquid impermeable backsheet, with the article of the present disclosure disposed between the topsheet and the backsheet. Such absorbent articles typically include sanitary napkins, diapers, and other incontinence articles.

Other fibers can be used to impart certain properties to the final article. For example, in filtration applications cellulose or glass fibers can be used in the article to allow the filter to wet out quickly. In abrasive articles, single-component fibers of at least one of nylon, rayon, polyester, or cotton may be useful.

Some Embodiments of the Disclosure

In a first embodiment, the present disclosure provides an article comprising:

multi-component fibers having external surfaces and comprising at least a first polymeric composition and a second polymeric composition, wherein at least a portion of the external surfaces of the multi-component fibers comprises the first polymeric composition, and wherein the multi-component fibers are adhered together and are non-fusing at a temperature of at least 110° C.; and

particles adhered at least to the first polymeric composition on the external surfaces of at least some of the multi-component fibers along their lengths, wherein the particles comprise at least one of activated carbon and superabsorbent polymer particles.

In a second embodiment, the present disclosure provides an article comprising:

a web of multi-component fibers having external surfaces and comprising at least a first polymeric composition and second polymeric composition, wherein at least a portion of the external surfaces of the multi-component fibers comprises the first polymeric composition, and wherein the multi-component fibers are adhered together and are non-fusing at a temperature of at least 110° C.; and

particles directly attached to the first polymeric composition on the external surfaces of at least some of the multi-component fibers along their lengths, wherein the particles comprise at least one of activated carbon, superabsorbent particles, and abrasive particles, and wherein the particles are distributed throughout the thickness of the web.

In a third embodiment, the present disclosure provides the article of the second embodiment, wherein the article is an abrasive article, wherein the particles are abrasive particles, and wherein the abrasive article does not include a size coat.

In a fourth embodiment, the present disclosure provides the article of the second embodiment, wherein the article is an abrasive article, and wherein the particles are abrasive particles comprising cerium oxide.

In a fifth embodiment, the present disclosure provides the article of the first or second embodiment, wherein the article comprises activated carbon, and may be, for example, a filter.

In a sixth embodiment, the present disclosure provides the article of any one of the first to fifth embodiments, wherein the first polymeric composition has a softening temperature of up to 150° C., wherein the second polymeric composition has a melting point of at least 130° C., and wherein the difference between the softening temperature of the first polymeric composition and the melting point of the second polymeric composition is at least 10° C.

In a seventh embodiment, the present disclosure provides the article of any one of the first to sixth embodiments, wherein the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² at a temperature of at least 80° C. measured at a frequency of one hertz.

In an eighth embodiment, the present disclosure provides the article of any one of the first to seventh embodiments, wherein the multi-component fibers are in a range from 10 micrometers to 300 micrometers in diameter.

In a ninth embodiment, the present disclosure provides the article of any one of the first to eighth embodiments, wherein the first polymeric composition is at least one of ethylene-vinyl alcohol copolymer, at least partially neutralized ethylene-methacrylic acid or ethylene-acrylic acid copolymer, polyurethane, polyoxymethylene, polypropylene, polyolefin, ethylene-vinyl acetate copolymer, polyester, polyamide, phenoxy, vinyl, or acrylic.

In a tenth embodiment, the present disclosure provides the article of any one of the first to ninth embodiments, wherein the second polymeric composition is at least one of an ethylene-vinyl alcohol copolymer, polyamide, polyoxymethylene, polypropylene, polyester, polyurethane, polysulfone, polyimide, polyetheretherketone, or polycarbonate.

In an eleventh embodiment, the present disclosure provides the article of any one of the first to tenth embodiments, wherein the multi-component fibers are non-fusing at a temperature of at least 150° C.

In a twelfth embodiment, the present disclosure provides the article of any one of the first to eleventh embodiments, wherein the multi-component fibers are in a range from 3 millimeters to 60 millimeters in length.

In a thirteenth embodiment, the present disclosure provides the article of any one of the first to twelfth embodiments, further comprising other, different fibers.

In a fourteenth embodiment, the present disclosure provides the article of any one of the first to thirteenth embodiments, wherein the particles have an average size in a range from 500 nanometers to 50 micrometers.

In a fifteenth embodiment, the present disclosure provides the article of any one of the first to fourteenth embodiments, wherein the particles have an average size up to twenty-five micrometers.

In a sixteenth embodiment, the present disclosure provides a method of making an article, the method comprising:

providing a mixture of particles and multi-component fibers, the multi-component fibers comprising at least a first polymeric composition and a second polymeric composition, and the particles comprising at least one of activated carbon, superabsorbent polymer particles, and abrasive particles; and

heating the mixture to a temperature at which the multi-component fibers are non-fusing and at which the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² when measured at a frequency of one hertz, wherein at least a portion of the mixture becomes adhered together to form a web, and wherein the particles are dispersed throughout the thickness of the web.

In a seventeenth embodiment, the present disclosure provides the method of the sixteenth embodiment, wherein the temperature is at least 80° C.

In an eighteenth embodiment, the present disclosure provides the method of the sixteenth or seventeenth embodiment, wherein the first polymeric composition has a softening temperature of up to 150° C., wherein the second polymeric composition has a melting point of at least 130° C., and wherein the difference between the softening temperature of the first polymeric composition and the melting point of the second polymeric composition is at least 10° C.

In a nineteenth embodiment, the present disclosure provides the method of any one of the sixteenth to eighteenth embodiments, wherein the multi-component fibers are in a range from 3 millimeters to 60 millimeters in length.

In a twentieth embodiment, the present disclosure provides the method of any one of the sixteenth to nineteenth embodiments, wherein the multi-component fibers are in a range from 10 to 300 micrometers in diameter.

In a twenty-first embodiment, the present disclosure provides the method of any one of the sixteenth to twentieth embodiments, wherein the article is a filter comprising activated carbon.

In a twenty-second embodiment, the present disclosure provides the method of any one of the sixteenth to twentieth embodiments, wherein the article is an abrasive article.

In a twenty-third embodiment, the present disclosure provides the method of any one of the sixteenth to twenty-second embodiments, wherein the mixture further comprises other, different fibers.

In a twenty-fourth embodiment, the present disclosure provides the method of any one of the sixteenth to twenty-third embodiments, wherein the mixture is introduced into a mold before the heating.

In order that this disclosure can be more fully understood, the following examples are set forth. The particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

EXAMPLES

In these examples, all percentages, proportions and ratios are by weight unless otherwise indicated. These abbreviations are used in the following examples: g=gram, min=minutes, in =inch, m=meter, cm=centimeter, mm=millimeter, μm=micrometer, ml=milliliter, psi=pounds per square inch, and Pa=Pascal.

Materials

The following materials were used in the preparation of Comparative Example A, Illustrative Example 1, and Examples 1-4:

TRADE DESIGNATION DESCRIPTION SUPPLIER “ULTRAMID B24” Polyamide 6 BASF North America, Florham Park, NJ “AMPLIFY IO 3702” Ethylene acrylic acid Dow Chemical, ionomer Midland, MI “DARCO-G60” Charcoal EMD Chemicals, Gibbstown, New Jersey “UNICER 166” Cerium oxide Universal Photonics, powder Hicksville, NY

Test Methods Glass Polishing:

A glass polishing test was performed using a 12 in (30.48 cm) overhead swing arm lapping machine (model “6Y-1” commercially available from Strasbaugh, San Luis Obispo, Calif.). The lapping machine comprised a movable polishing head having a diameter of about 6 in (15.24 cm), and a lower platen, onto which an abrasive article was mounted. A glass substrate having a thickness of about 0.125 in (0.31 cm) (part number “06120256” obtained from SwiftGlass, Elmira Heights, N.Y.) was mounted on the polishing head. The polishing head was run in counter clock-wise direction at 58 rpm with an oscillating sweep across the surface (8 inch (20.32 cm) sweep) and a down force of about 1.5 psi (1.0×10⁴ Pa). The lower platen was run at 74 rpm in counter clock-wise direction. A polishing slurry comprising 5% wt of “UNICER 166” cerium oxide in deionized water was deposited on the center of the lower platen at flow rate of about 15 ml/min. The polishing slurry had a pH of about 4. Glass substrates were weighed before and after 15 minutes of polishing (1 cycle). 12 samples of each abrasive article were submitted to a polishing cycle and reduction in thickness indicated by average cut rate (expressed in angstrom (Å) per minute). The thickness was calculated according to the following equation:

Thickness=Weight of glass substrate/(substrate density×substrate area)  (1)

Comparative Example a and Example 1

Articles comprising multi-component fibers and particle composites were prepared as described below.

Multi-component fibers were prepared as generally described in Example 1 of U.S. Pat. No. 4,406,850 (Hills), incorporated herein by reference, except (a) the die was heated to the temperature listed in Table 1, below; (b) the extrusion die had sixteen orifices laid out as two rows of eight holes, wherein the distance between holes was 12.7 mm (0.50 in) with square pitch, and the die had a transverse length of 152.4 mm (6.0 inches); (c) the hole diameter was 1.02 mm (0.040 in) and the length to diameter ratio was 4.0; (d) the relative extrusion rates in grams per hole per minute of the two streams are reported in Table 1; (e) the fibers were conveyed downwards a distance reported in Table 1 and air quenched by compressed air and wound on a core; and (f) the spinning speed was adjusted by a pull roll to rates reported in Table 1.

TABLE 1 Core Sheath Rate, Rate, grams grams Pull Roll Multi- per per Die Speed, Distance to component hole per hole per Temperature, Meters/ Quench, Fiber minute minute ° C. minute centimeters Fiber 1 0.25 0.24 220 950 36

The core material (second polymeric composition) for the multi-component fibers was “ULTRAMID B24” polyamide 6. The sheath material (first polymeric composition) was “AMPLIFY IO 3702” ethylene-acrylic acid ionomer. The multi-component fibers had a fiber density of about 1.02 g/mL, an average diameter of about 20 μm and were chopped to a length of about 6 mm.

The softening temperature of “AMPLIFY IO 3702” ethylene acrylic acid ionomer was found to be 110° C. when evaluated using the method described in the Detailed Description (page 6, line 27 to page 7, line 2). That is, the crossover temperature was 110° C. Also using this method except using a frequency of 1.59 Hz, the elastic modulus was found to be 8.6×10⁴ N/m² at 100° C., 6.1×10⁴N/m² at 110° C., 4.3×10⁴ N/m² at 120° C., 2.8×10⁴ N/m² at 130° C., 1.9×10⁴ N/m² at 140° C., 1.2×10⁴N/m² at 150° C., and 7.6×10³ N/m² at 160° C. The melting point of “AMPLIFY IO 3702” ethylene acrylic acid ionomer is reported to be 92.2° C. by Dow Chemical in a data sheet dated 2011. The melting point of “ULTRAMID B24” polyamide 6 is reported to be 220° C. by BASF in a product data sheet dated September 2008. The grade of the “ULTRAMID B24” polyamide 6 did not contain titanium dioxide. A fiber having the same sheath except obtained under trade designation “SURYLYN 1702” from E. I. duPont de Nemours & Company, Wilmington, Del., which is reported in a product data sheet dated 2010 to have a melting point of 93° C. and the same melt flow rate as “AMPLIFY IO 3702” ethylene acrylic acid ionomer, and a core made from “ZYTEL RESIN 101NC010” from E.I. DuPont de Nemours & Company was evaluated using the method described on page 6, lines 4 to 11. The fiber diameter changed less than 10% when the evaluation was carried out at 150° C. The fibers were found to be non-fusing. See Example 5 of U.S. Pat. App. Pub. No. 2010/0272994 (Carlson et al.).

Multi-component fibers were prepared by opening up fiber bundles using a Mr. Coffee grinder (model “IDS 55” obtained from Mr. Coffee, Boca Raton, Fla.) for 15-30 seconds until the fiber was lofty with no visible bundles. About 5 g of the multi-component fibers and 1 g of “DARCO-G60” charcoal were added to a glass jar. The glass jar was closed and tumbled gently at room temperature on a 5-Rollver Oven (obtained from OFITE, Houston, Tex.) at a setting of 30% for 30 minutes. The fiber charcoal mixture was then removed from the glass jar and a minimal amount of loose carbon (about 0.05 g) was observed left in the glass jar.

About 6 g of fiber-charcoal mixtures were placed into first and second hollow metal tubes, each measuring 2 in (5 cm) in diameter and 12 in (30.5 cm) in length. The first tube was then heated to 150° C. for 60 minutes in an oven obtained from H & C Thermal Systems, Columbia, Md., under the trade designation “THERMOLYNE OVEN SERIES 9000”. The fiber-charcoal mixture in the first tube formed a fiber-charcoal composite, and this sample is hereinafter referred to as Example 1. The fiber-charcoal mixture in the second tube (not heated) did not form a composite and is hereinafter referred to as Comparative Example A. Upon cooling to room temperature, 50 g of water was run through each tube and the throughput water was collected in a beaker. The presence of charcoal particles in the collected water was visually determined. No charcoal and/or fiber particles were detected in the water collected from the first tube. Charcoal and fiber particles were clearly visible in the water collected from the second tube even after rinsing.

Illustrative Example 1

Multi-component fibers were prepared as described in Example 1. The multi-component fibers were subsequently air laid to form a fiber web having a density of about 400 g/m². The web was thermally bonded using a 5.5 m long drying oven further comprising a conveyor belt. The temperature in the drying oven was set to 120° C. The speed of the conveyor belt was of about 1 m/min. At the end of the drying oven, a press roller was used to set the final thickness of the web to 0.75 inch (1.9 cm).

Example 2

A fiber web was prepared as described in Illustrative Example 1. “UNICER 166” cerium oxide particles having a particle size of about 0.5 μm were then dropped onto the fiber web at a weight ratio of about 4:1 cerium oxide: multi-component fibers. The particle-loaded web comprising a first surface and a second surface, opposite the first surface, was hand shaken to allow the particles to penetrate the web. One layer of a 2-mil (50 μm) thick PTFE film-lined (commercially available from Plastics International, Eden Prairie, Minn.) was disposed on each surface of the particle-loaded web. A 2 mm thick aluminum perforated plate was placed adjacent the PTFE film on the first surface. The perforated plate comprised several 3 mm diameter perforations. The perforations were spaced 5 mm apart (center to center) in a given line. The lines were staggered and spaced 4 mm apart (center to center). The particle-loaded web was then placed under a hot press at a temperature of 80° C., under a pressure of about 2000 psi (13.8 MPa) for 20 minutes, forming a fiber-particle composite. The aluminum plate was removed from the first surface to form an abrasive article comprising a patterned protruded surface, as shown in FIG. 5.

Abrasive articles of Illustrative Example 1 and Example 2 were used for glass polishing, as described in the test method above. Results are reported in Table 2, below.

TABLE 2 Samples Average cut rate (Å/minute) Illustrative Example 1 1000 Example 2 1200

Various modifications and alterations to this disclosure will become apparent to those skilled in the art without departing from the scope and spirit of this disclosure. It should be understood that this disclosure is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the disclosure intended to be limited only by the claims set forth herein as follows. 

1. An article comprising: multi-component fibers having external surfaces and comprising at least a first polymeric composition and a second polymeric composition, wherein at least a portion of the external surfaces of the multi-component fibers comprises the first polymeric composition, and wherein the multi-component fibers are adhered together and are non-fusing at a temperature of at least 110° C.; and particles adhered at least to the first polymeric composition on the external surfaces of at least some of the multi-component fibers along their lengths, wherein the particles comprise at least one of activated carbon or superabsorbent polymer particles.
 2. An article comprising: a web of multi-component fibers having external surfaces and comprising at least a first polymeric composition and second polymeric composition, wherein at least a portion of the external surfaces of the multi-component fibers comprises the first polymeric composition, and wherein the multi-component fibers are adhered together and are non-fusing at a temperature of at least 110° C.; and particles directly attached to the first polymeric composition on the external surfaces of at least some of the multi-component fibers along their lengths, wherein the particles comprise at least one of activated carbon, superabsorbent polymer particles, or abrasive particles, and wherein the particles are distributed throughout the thickness of the web.
 3. The article of claim 2, wherein the article is an abrasive article, wherein the particles are abrasive particles, and wherein the abrasive article does not include a size coat.
 4. The article of claim 2, wherein the particles are abrasive particles comprising cerium oxide.
 5. The article of claim 1, wherein the article is a filter comprising activated carbon.
 6. The article of claim 2, wherein the first polymeric composition has a softening temperature of up to 150° C., wherein the second polymeric composition has a melting point of at least 130° C., and wherein the difference between the softening temperature of the first polymeric composition and the melting point of the second polymeric composition is at least 10° C.
 7. The article of claim 2, wherein the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² at a temperature of at least 80° C. measured at a frequency of one hertz.
 8. The article of claim 2, wherein the multi-component fibers are in a range from 10 micrometers to 300 micrometers in diameter and in a range from 3 millimeters to 60 millimeters in length.
 9. The article of claim 2, wherein the multi-component fibers are non-fusing at a temperature of at least 150° C.
 10. The article of claim 2, further comprising other, different fibers.
 11. The article of claim 2, wherein the particles have an average size up to twenty-five micrometers.
 12. A method of making an article, the method comprising: providing a mixture of particles and multi-component fibers, the multi-component fibers comprising at least a first polymeric composition and a second polymeric composition, and the particles comprising at least one of activated carbon, superabsorbent polymer particles, or abrasive particles; and heating the mixture to a temperature at which the multi-component fibers are non-fusing and at which the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² when measured at a frequency of one hertz, wherein at least a portion of the mixture becomes adhered together to form a web, and wherein the particles are dispersed throughout the thickness of the web.
 13. The method of claim 12, wherein the temperature is at least 80° C.
 14. The method of claim 12, wherein the first polymeric composition has a softening temperature of up to 150° C., wherein the second polymeric composition has a melting point of at least 130° C., and wherein the difference between the softening temperature of the first polymeric composition and the melting point of the second polymeric composition is at least 10° C.
 15. The method of claim 12, wherein the article is a filter comprising activated carbon, or wherein the article is an abrasive article.
 16. The article of claim 1, wherein the article is a filter comprising activated carbon.
 17. The article of claim 1, wherein the first polymeric composition has a softening temperature of up to 150° C., wherein the second polymeric composition has a melting point of at least 130° C., and wherein the difference between the softening temperature of the first polymeric composition and the melting point of the second polymeric composition is at least 10° C.
 18. The article of claim 1, wherein the first polymeric composition has an elastic modulus of less than 3×10⁵ N/m² at a temperature of at least 80° C. measured at a frequency of one hertz.
 19. The article of claim 1, wherein the multi-component fibers are in a range from 3 millimeters to 60 millimeters in length.
 20. The article of claim 1, further comprising other, different fibers. 